Method of forming a structure on a substrate

ABSTRACT

The invention relates to depositing a layer on a substrate in a reactor, by:
         introducing a first precursor comprising a silicon halide in the reactor;   introducing a second precursor in the reactor;   providing an energy source to create a plasma from the second precursor so that the second precursor reacts with the first precursor until a primary layer comprising silicon and second precursor of a desired thickness is formed;   stop introducing the second precursor; and,   subsequently introducing the silicon halide in the reactor at a temperature causing decomposition of the silicon halide precursor to provide a substantially pure amorphous silicon layer on top of the primary layer.

FIELD OF INVENTION

The present disclosure generally relates to methods and systems formanufacturing electronic devices. More particularly, the disclosurerelates to methods for providing a structure by depositing a layer on asubstrate in a reactor.

BACKGROUND

As the trend has pushed structures in semiconductor devices to smallerand smaller sizes, different patterning techniques have arisen toproduce these structures. These techniques include spacer defined doubleor quadruple patterning, (immersion) lithography (193i), extremeultraviolet lithography (EUV), and directed self-assembly (DSA)lithography. Lithography may be combined with spacer defined double orquadruple patterning.

In these techniques it may be advantageous to transfer the pattern ofthe polymer resist to a hardmask. A hardmask is a material used insemiconductor processing as an etch mask with a good etching resistanceand etching selectivity to produce small structures.

Spacers are also widely used in semiconductor manufacturing to protectagainst subsequent processing steps. For example, silicon nitridespacers formed beside gate electrodes can be used as a mask to protectunderlying source/drain areas during doping or implanting steps. As thephysical geometry of structures of semiconductor devices shrinks, thegate electrode spacer becomes smaller and smaller. The spacer width islimited by the silicon nitride thickness that can be depositedconformably over the dense gate electrodes lines with a plasma enhancedatomic layer deposition (PEALD) or chemical vapor deposition (PECVD)process.

Hardmasks or spacers produced by current PEALD or PECVD silicon nitrideprocesses may have a wet etch rate which may be too high. It istherefore advantageous to produce a layer for a hardmask or a spacerwith a higher etching resistance and etching selectivity. As a result, alayer with advanced properties may be required.

SUMMARY

In accordance with at least one embodiment of the invention there isprovided a method of providing a structure by depositing a layer on asubstrate in a reactor, the method comprising:

introducing a first precursor comprising a silicon halide in thereactor;

introducing a second precursor in the reactor;

providing an energy source to create a plasma from the second precursorso that the second precursor reacts with the first precursor until aprimary layer comprising silicon and second precursor of a desiredthickness is formed;

stop introducing the second precursor; and,

subsequently introducing the silicon halide in the reactor at atemperature causing decomposition of the silicon halide precursor toprovide a substantially pure amorphous silicon layer on top of theprimary layer. The layer comprising the primary layer comprising siliconand second precursor and a substantially pure amorphous silicon layer ontop may have a an improved etch rate in hydro fluoride HF. The layer maybe easily deposited because no different first precursor is required forthe primary and the substantially pure amorphous layer. Further nodifferent tool nor any transfer to a different reaction chamber may benecessary. The substantially pure amorphous silicon layer may beselectively deposited on the primary layer such that it is onlydeposited on top of this layer and not on other layers. It may also bedeposited on the complete surface.

According to a further embodiment there is provided a method ofproviding a structure by depositing a layer on a substrate in a reactor,the method comprising:

introducing a first precursor comprising silicon halide in the reactorat a temperature causing decomposition of the silicon halide precursorto provide a substantially pure amorphous silicon,

subsequently introducing a second precursor in the reactor; and,

providing an energy source to create a plasma from the second precursorso that the second precursor reacts with the first precursor until aprimary layer comprising silicon and second precursor of a desiredthickness is formed.

The layer comprising the substantially pure amorphous silicon layer andthe primary layer comprising silicon and second precursor on top mayhave a an improved etch rate. The pure amorphous silicon layer mayprotect an underlying layer from the second precursor which may beadvantageous.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE FIGURES

These and other features, aspects, and advantages of the inventiondisclosed herein are described below with reference to the drawings ofcertain embodiments, which are intended to illustrate and not to limitthe invention.

FIG. 1 is a flowchart in accordance with at least one embodiment of theinvention.

FIGS. 2A-2B show images from layers deposited according to an embodimenton some high aspect ratio structures.

It may be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale tohelp improve understanding of illustrated embodiments of the presentdisclosure.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail.

The primary layer may be a silicon nitride film which may have a widevariety of applications, as will be apparent to the skilled artisan,such as in planar logic, DRAM, and NAND Flash devices. Morespecifically, conformal silicon nitride thin films that display uniformetch behavior have a wide variety of applications, both in thesemiconductor industry and also outside of the semiconductor industry.

According to some embodiments of the present disclosure, various siliconnitride films and precursors and methods for depositing those films byatomic layer deposition (ALD) are provided. Importantly, in someembodiments the silicon nitride films have a relatively uniform etchrate for both the vertical and the horizontal portions, when depositedonto 3-dimensional structures. Such three-dimensional structures mayinclude, for example and without limitation, FinFETS or other types ofmultiple gate FETs.

Thin film layers comprising silicon nitride can be deposited byplasma-enhanced atomic layer deposition (PEALD) or chemical vapordeposition (PECVD) type processes or by thermal ALD processes. In someembodiments a silicon nitride thin film is deposited over a threedimensional structure, such as a fin in the formation of a finFETdevice, and/or in the application of spacer defined double patterning(SDDP) and/or spacer defined quadruple patterning (SDQP). In someembodiments a silicon nitride thin film is deposited over a flat layeras a hard mask and subsequent layer are positioned on top forlithographic processing.

The formula of the silicon nitride is generally referred to herein asSiN for convenience and simplicity. However, the skilled artisan willunderstand that the actual formula of the silicon nitride, representingthe Si:N ratio in the film and excluding hydrogen or other impurities,can be represented as SiNx, where x varies from about 0.5 to about 2.0,as long as some Si—N bonds are formed. In some cases, x may vary fromabout 0.9 to about 1.7, from about 1.0 to about 1.5, or from about 1.2to about 1.4. In some embodiments silicon nitride is formed where Si hasan oxidation state of +IV and the amount of nitride in the materialmight vary.

ALD-type processes are based on controlled, generally self-limitingsurface reactions. Gas phase reactions are typically avoided bycontacting the substrate alternately and sequentially with theprecursors. Vapor phase precursors are separated from each other in thereaction chamber, for example, by removing excess precursors and/orreaction byproducts between precursor pulses. The precursors may beremoved from proximity with the substrate surface with the aid of apurge gas and/or vacuum. In some embodiments excess precursors and/orreaction byproducts are removed from the reaction space by purging, forexample with an inert gas.

The methods presented herein provide for deposition of SiN thin films onsubstrate surfaces. Geometrically challenging applications are alsopossible due to the nature of ALD-type processes. According to someembodiments, ALD-type processes are used to form SiN thin films onsubstrates such as integrated circuit workpieces, and in someembodiments on three-dimensional structures on the substrates. In someembodiments, ALD type processes comprise alternate and sequentialcontact of the substrate with a silicon precursor and a nitrogenprecursor. In some embodiments, a silicon precursor contacts thesubstrate such silicon species adsorb onto the surface of the substrate.In some embodiments, the silicon species may be same as the siliconprecursor, or may be modified in the adsorbing step, such as by losingone or more ligands.

According to certain embodiments, a silicon nitride thin film may beformed on a substrate by an ALD-type process comprising multiple siliconnitride deposition cycles, each silicon nitride deposition cyclecomprising:

(1) contacting a substrate with a first silicon precursor such thatsilicon species adsorb on the substrate surface;

(2) contacting the substrate with a nitrogen precursor; and

(3) repeating steps (1) and (2) as many times as required to achieve athin film of a desired thickness and composition. Excess precursors maybe removed from the vicinity of the substrate, for example by purgingfrom the reaction space with an inert gas, after each contacting step.

PEALD Processes

In some embodiments, plasma enhanced ALD (PEALD) processes are used todeposit SiN layers. Briefly, a substrate or workpiece is placed in areaction chamber and subjected to alternately repeated surfacereactions. In some embodiments, thin SiN films are formed by repetitionof a self-limiting ALD cycle. Preferably, for forming SiN films, eachALD cycle comprises at least two distinct phases. The provision andremoval of a precursor from the reaction space may be considered aphase. In a first phase, a first precursor comprising silicon isprovided and forms no more than about one monolayer on the substratesurface. This precursor is also referred to herein as “the siliconprecursor,” “silicon-containing precursor,” “silicon halide”, or“silicon reactant” and may be, for example, H₂SiI₂.

In a second phase, a second precursor comprising a reactive species isprovided and may convert adsorbed silicon species to silicon nitride. Insome embodiments the second precursor comprises a nitrogen precursor. Insome embodiments, the reactive species comprises an excited species. Insome embodiments the second precursor comprises a species from anitrogen containing plasma. In some embodiments, the second precursorcomprises nitrogen radicals, nitrogen atoms and/or nitrogen plasma. Insome embodiments, the second precursor may comprise N-containing plasmaor a plasma comprising N. In some embodiments, the second precursor maycomprise a plasma comprising N-containing species. In some embodimentsthe second precursor may comprise nitrogen atoms and/or N* radicals. Thesecond precursor may comprise other species that are not nitrogenprecursors. In some embodiments, the second precursor may comprise aplasma of hydrogen, radicals of hydrogen, or atomic hydrogen in one formor another. In some embodiments, the second precursor may comprise aspecies from a noble gas, such as He, Ne, Ar, Kr, or Xe, preferably Aror He, for example as radicals, in plasma form, or in elemental form.These reactive species from noble gases do not necessarily contributematerial to the deposited film, but can in some circumstances contributeto film growth as well as help in the formation and ignition of plasma.In some embodiments a gas that is used to form a plasma may flowconstantly throughout the deposition process but only be activatedintermittently. In some embodiments, the second precursor does notcomprise a species from a noble gas, such as Ar. Thus, in someembodiments the adsorbed silicon precursor is not contacted with areactive species generated by a plasma from Ar

Additional phases may be added and phases may be removed as desired toadjust the composition of the final film.

One or more of the precursors may be provided with the aid of a carriergas, such as Ar or He. In some embodiments the first precursor and thesecond precursor are provided with the aid of a carrier gas.

In some embodiments, two of the phases may overlap, or be combined. Forexample, the silicon precursor and the second precursor may be providedsimultaneously in pulses that partially or completely overlap. Inaddition, although referred to as the first and second phases, and thefirst and second precursors, the order of the phases may be varied, andan ALD cycle may begin with any one of the phases. That is, unlessspecified otherwise, the precursors can be provided in any order, andthe process may begin with any of the precursors.

As discussed in more detail below, in some embodiments for depositing asilicon nitride film, one or more deposition cycles begin with provisionof the silicon precursor, followed by the second precursor. In otherembodiments deposition may begin with provision of the second precursor,followed by the silicon precursor.

In some embodiments the substrate on which deposition is desired, suchas a semiconductor workpiece, is loaded into a reactor. The reactor maybe part of a cluster tool in which a variety of different processes inthe formation of an integrated circuit are carried out. In someembodiments a flow-type reactor is utilized. In some embodiments ashower head type of reactor is utilized. In some embodiments, a spacedivided reactor is utilized. In some embodiments a high-volumemanufacturing-capable single wafer ALD reactor is used. In otherembodiments a batch reactor comprising multiple substrates is used. Forembodiments in which batch ALD reactors are used, the number ofsubstrates is preferably in the range of 10 to 200, more preferably inthe range of 50 to 150, and most preferably in the range of 100 to 130.

Exemplary single wafer reactors, designed specifically to enhance ALDprocesses, are commercially available from ASM America, Inc. (Phoenix,Ariz.) under the tradenames Pulsar® 2000 and Pulsar® 3000 and ASM JapanK.K (Tokyo, Japan) under the tradename Eagle® XP, XP8 and Dragon®.Exemplary batch ALD reactors, designed specifically to enhance ALDprocesses, are commercially available from and ASM Europe B.V (Almere,Netherlands) under the tradenames A400™ and A412™.

In some embodiments, if necessary, the exposed surfaces of the workpiececan be pretreated to provide reactive sites to react with the firstphase of the ALD process. In some embodiments a separate pretreatmentstep is not required. In some embodiments the substrate is pretreated toprovide a desired surface termination. In some embodiments the substrateis pretreated with plasma.

Excess precursor and reaction byproducts, if any, are removed from thevicinity of the substrate, and in particular from the substrate surface,between precursor pulses. In some embodiments the reaction chamber ispurged between precursor pulses, such as by purging with an inert gas.The flow rate and time of each precursor, is tunable, as is the removalstep, allowing for control of the quality and various properties of thefilms.

As mentioned above, in some embodiments a gas is provided to thereaction chamber continuously during each deposition cycle, or duringthe entire ALD process, and reactive species are provided by generatinga plasma in the gas, either in the reaction chamber or upstream of thereaction chamber. In some embodiments the plasma gas comprises nitrogen.In some embodiments the plasma gas is nitrogen. In other embodiments theplasma gas may comprise helium, hydrogen, or argon. In some embodimentsthe plasma gas is helium, hydrogen or argon. The plasma gas such usnitrogen, argon, helium or hydrogen may have a flow of 1 to 10,preferably 2 to 8, more preferably 3 to 6 and most preferably around 5slm. The gas may also serve as a purge gas for the first and/or secondprecursor (or reactive species).

For example, flowing nitrogen may serve as a purge gas for a firstsilicon precursor and also serve as a second precursor (as a source ofreactive species). In some embodiments, nitrogen, argon, or helium mayserve as a purge gas for a first precursor and a source of excitedspecies for converting the silicon precursor to the silicon nitridefilm. In some embodiments the gas in which the plasma is generated doesnot comprise argon and the adsorbed silicon precursor is not contactedwith a reactive species generated by a plasma from Ar.

The cycle is repeated until a film of the desired thickness andcomposition is obtained. In some embodiments the deposition parameters,such as the flow rate, flow time, purge time, and/or precursorsthemselves, may be varied in one or more deposition cycles during theALD process in order to obtain a film with the desired characteristics.In some embodiments, hydrogen and/or hydrogen plasma are not provided ina deposition cycle, or in the deposition process.

The term “pulse” may be understood to comprise feeding precursor intothe reaction chamber for a predetermined amount of time. The term“pulse” does not restrict the length or duration of the pulse and apulse can be any length of time.

In some embodiments, the silicon precursor is provided first. After aninitial surface termination, if necessary or desired, a first siliconprecursor pulse is supplied to the workpiece. In accordance with someembodiments, the first precursor pulse comprises a carrier gas flow anda volatile silicon halide species, such as H₂SiI₂, that is reactive withthe workpiece surfaces of interest. Accordingly, the silicon precursoradsorbs upon these workpiece surfaces. The first precursor pulseself-saturates the workpiece surfaces such that any excess constituentsof the first precursor pulse do not further react with the molecularlayer formed by this process. The carrier gas may have a flow of 0.5 to8, preferably 1 to 5, more preferably 2 to 3 and most preferably around2.8 slm.

The first silicon precursor pulse is preferably supplied in gaseousform. The silicon precursor gas is considered “volatile” for purposes ofthe present description if the species exhibits sufficient vaporpressure under the process conditions to transport the species to theworkpiece in sufficient concentration to saturate exposed surfaces.

In some embodiments the silicon precursor pulse is from about 0.05seconds to about 5.0 seconds, about 0.1 seconds to about 3 seconds orabout 0.2 seconds to about 1.0 seconds. The optimum pulsing time can bereadily determined by the skilled artisan based on the particularcircumstances.

In some embodiments the silicon precursor consumption rate is selectedto provide a desired dose of precursor to the reaction space. precursorconsumption refers to the amount of precursor consumed from theprecursor source, such as a precursor source bottle, and can bedetermined by weighing the precursor source before and after a certainnumber of deposition cycles and dividing the mass difference by thenumber of cycles. In some embodiments the silicon precursor consumptionis more than about 0.1 mg/cycle. In some embodiments the siliconprecursor consumption is about 0.1 mg/cycle to about 50 mg/cycle, about0.5 mg/cycle to about 30 mg/cycle or about 2 mg/cycle to about 20mg/cycle. In some embodiments the minimum preferred silicon precursorconsumption may be at least partly defined by the reactor dimensions,such as the heated surface area of the reactor. In some embodiments in ashowerhead reactor designed for 300 mm silicon wafers, silicon precursorconsumption is more than about 0.5 mg/cycle, or more than about 2.0mg/cycle. In some embodiments the silicon precursor consumption is morethan about 5 mg/cycle in a showerhead reactor designed for 300 mmsilicon wafers. In some embodiments the silicon precursor consumption ismore than about 1 mg/cycle, preferably more than 5 mg/cycle at reactiontemperatures below about 400° C. in a showerhead reactor designed for300 mm silicon wafers.

After sufficient time for a molecular layer to adsorb on the substratesurface, excess first silicon precursor is then removed from thereaction space. In some embodiments the excess first precursor is purgedby stopping the flow of the first chemistry while continuing to flow acarrier gas or purge gas for a sufficient time to diffuse or purgeexcess precursors and reaction by-products, if any, from the reactionspace. In some embodiments the excess first precursor is purged with theaid of inert gas, such as nitrogen or argon, that is flowing throughoutthe ALD cycle.

In some embodiments, the first precursor is purged for about 0.1 secondsto about 10 seconds, about 0.3 seconds to about 5 seconds or about 0.3seconds to about 1 second. Provision and removal of the siliconprecursor can be considered the first or silicon phase of the ALD cycle.

In the second phase, a second precursor comprising a reactive species,such as nitrogen plasma is provided to the workpiece. Nitrogen, N2, isflowed continuously to the reaction chamber during each ALD cycle insome embodiments. Nitrogen plasma may be formed by generating a plasmain nitrogen in the reaction chamber or upstream of the reaction chamber,for example by flowing the nitrogen through a remote plasma generator.

In some embodiments, plasma is generated in flowing H2 and N2 gases. Insome embodiments the H2 and N2 are provided to the reaction chamberbefore the plasma is ignited or nitrogen and hydrogen atoms or radicalsare formed. Without being bound to any theory, it is believed that thehydrogen may have a beneficial effect on the ligand removal step i.e. itmay remove some of the remaining ligands or have other beneficialeffects on the film quality. In some embodiments the H2 and N2 areprovided to the reaction chamber continuously and nitrogen and hydrogencontaining plasma, atoms or radicals is created or supplied when needed.

Typically, the second precursor, for example comprising nitrogen plasma,is provided for about 0.1 seconds to about 10 seconds. In someembodiments the second precursor, such as nitrogen plasma, is providedfor about 0.1 seconds to about 10 seconds, 0.5 seconds to about 5seconds or 0.5 seconds to about 2.0 seconds. However, depending on thereactor type, substrate type and its surface area, the second precursorpulsing time may be even higher than about 10 seconds. In someembodiments, pulsing times can be on the order of minutes. The optimumpulsing time can be readily determined by the skilled artisan based onthe particular circumstances.

In some embodiments the second precursor is provided in two or moredistinct pulses, without introducing another precursor in between any ofthe two or more pulses. For example, in some embodiments a nitrogenplasma is provided in two or more, preferably in two, sequential pulses,without introducing a Si-precursor in between the sequential pulses. Insome embodiments during provision of nitrogen plasma two or moresequential plasma pulses are generated by providing a plasma dischargefor a first period of time, extinguishing the plasma discharge for asecond period of time, for example from about 0.1 seconds to about 10seconds, from about 0.5 seconds to about 5 seconds or about 1.0 secondsto about 4.0 seconds, and exciting it again for a third period of timebefore introduction of another precursor or a removal step, such asbefore the Si-precursor or a purge step. Additional pulses of plasma canbe introduced in the same way. In some embodiments a plasma is ignitedfor an equivalent period of time in each of the pulses.

Nitrogen plasma may be generated by applying RF power of from about 10 Wto about 2000 W, preferably from about 50 W to about 1500 W, morepreferably from about 100 W to about 800 W in some embodiments. In someembodiments the RF power density may be from about 0.02 W/cm² to about2.0 W/cm², preferably from about 0.05 W/cm² to about 1.5 W/cm². The RFpower may be applied to nitrogen that flows during the nitrogen plasmapulse time, that flows continuously through the reaction chamber, and/orthat flows through a remote plasma generator. Thus in some embodimentsthe plasma is generated in situ, while in other embodiments the plasmais generated remotely. In some embodiments a showerhead reactor isutilized and plasma is generated between a substrate holder (on top ofwhich the substrate is located) and a showerhead plate. In someembodiments the gap between the substrate holder and showerhead plate isfrom about 0.1 cm to about 20 cm, from about 0.5 cm to about 5 cm, orfrom about 0.8 cm to about 3.0 cm.

After a time period sufficient to completely saturate and react thepreviously adsorbed molecular layer with the nitrogen plasma pulse, anyexcess precursor and reaction byproducts are removed from the reactionspace. As with the removal of the first precursor, this step maycomprise stopping the generation of reactive species and continuing toflow the inert gas, such as nitrogen or argon for a time periodsufficient for excess reactive species and volatile reaction by-productsto diffuse out of and be purged from the reaction space. In otherembodiments a separate purge gas may be used. The purge may, in someembodiments, be from about 0.1 seconds to about 10 seconds, about 0.1seconds to about 4 seconds or about 0.1 seconds to about 0.5 seconds.Together, the nitrogen plasma provision and removal represent a second,reactive species phase in a silicon nitride atomic layer depositioncycle.

The two phases together represent one ALD cycle, which is repeated toform silicon nitride thin films of a desired thickness for the primarylayer. While the ALD cycle is generally referred to herein as beginningwith the silicon phase, it is contemplated that in other embodiments thecycle may begin with the reactive species phase. One of skill in the artwill recognize that the first precursor phase generally reacts with thetermination left by the last phase in the previous cycle. Thus, while noprecursor may be previously adsorbed on the substrate surface or presentin the reaction space if the reactive species phase is the first phasein the first ALD cycle, in subsequent cycles the reactive species phasewill effectively follow the silicon phase. In some embodiments one ormore different ALD cycles are provided in the deposition process.

According to some embodiments of the present disclosure, PEALD reactionsmay be performed at temperatures ranging from about 25° C. to about 700°C., preferably from about 50° C. to about 600° C., more preferably fromabout 100° C. to about 450° C., and most preferably from about 200° C.to about 400° C. In some embodiments, the optimum reactor temperaturemay be limited by the maximum allowed thermal budget. Therefore, in someembodiments the reaction temperature is from about 300° C. to about 400°C. In some applications, the maximum temperature is around about 400°C., and, therefore the PEALD process is run at that reactiontemperature.

According to some embodiments of the present disclosure, the pressure ofthe reaction chamber during processing is maintained at from about 0.01torr to about 50 torr, preferably from about 0.1 torr to about 10 torr.

Si Precursors

A number of suitable silicon halide precursors can be used in thepresently disclosed PEALD processes. At least some of the suitableprecursors may have the following general formula:H_(2n+2−y−z)Si_(n)X_(y)A_(z)  (1)wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), X is I or Br, and A is a halogen other than X, preferably n=1-5and more preferably n=1-3 and most preferably 1-2.

According to some embodiments, silicon halide precursors may compriseone or more cyclic compounds. Such precursors may have the followinggeneral formula:H_(2n+2−y−z)Si_(n)X_(y)A_(z)  (2)wherein the formula (2) compound is cyclic compound, n=3-10, y=1 or more(and up to 2n−z), z=0 or more (and up to 2n−y), X is I or Br, and A is ahalogen other than X, preferably n=3-6.

According to some embodiments, silicon halide precursors may compriseone or more iodosilanes. Such precursors may have the following generalformula:H_(2n+2−y−z)Si_(n)I_(y)A_(z)  (3)wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), and A is a halogen other than I, preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2.

According to some embodiments, some silicon halide precursors maycomprise one or more cyclic iodosilanes. Such precursors may have thefollowing general formula:H_(2n+2−y−z)Si_(n)I_(y)A_(z)  (4)wherein the formula (4) compound is a cyclic compound, n=3-10, y=1 ormore (and up to 2n−z), z=0 or more (and up to 2n−y), and A is a halogenother than I, preferably n=3-6.

According to some embodiments, some silicon halide precursors maycomprise one or more bromosilanes. Such precursors may have thefollowing general formula:H_(2n+2−y−z)Si_(n)Br_(y)A_(z)  (5)wherein, n=1-10, y=1 or more (and up to 2n+2−z), z=0 or more (and up to2n+2−y), and A is a halogen other than Br, preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2.

According to some embodiments, some silicon halide precursors maycomprise one or more cyclic bromosilanes. Such precursors may have thefollowing general formula:H_(2n+2−y−z)Si_(n)Br_(y)A_(z)  (6)wherein the formula (6) compound is a cyclic compound, n=3-10, y=1 ormore (and up to 2n−z), z=0 or more (and up to 2n−y), and A is a halogenother than Br, preferably n=3-6.

According to some embodiments, preferred silicon halide precursorscomprise one or more iodosilanes. Such precursors may have the followinggeneral formula:H_(2n+2−y−z)Si_(n)I_(y)  (7)wherein, n=1-5, y=1 or more (up to 2n+2), preferably n=1-3 and morepreferably n=1-2.

According to some embodiments, preferred silicon halide precursorscomprise one or more bromosilanes. Such precursors may have thefollowing general formula:H_(2n+2−y−z)Si_(n)I_(y)  (8)wherein, n=1-5, y=1 or more (up to 2n+2), preferably n=1-3 and morepreferably n=1-2.

According to some embodiments of a PEALD process, suitable siliconhalide precursors can include at least compounds having any one of thegeneral formulas (1) through (8). In general formulas (1) through (8),halides/halogens can include F, Cl, Br and I. In some embodiments, asilicon halide precursor comprises SiI₄, HSiI₃, H₂SiI₂, H₃SiI, Si₂I₆,HSi₂I₅, H₂Si₂I₄, H₃Si₂I₃, H₄Si₂I₂, H₅Si₂I, or Si₃I₈. In someembodiments, a silicon precursor comprises one of HSiI₃, H₂SiI₂, H₃SiI,H₂Si₂I₄, H₄Si₂I₂, and H₅Si₂I. In some embodiments the silicon halideprecursor comprises two, three, four, five or six of HSiI₃, H₂SiI₂,H₃SiI, H₂Si₂I₄, H₄Si₂I₂, and H₅Si₂I, including any combinations thereof.

In certain embodiments, the Si halide precursor is H₂SiI₂. In someembodiments, Si halide precursors of formulas (9)-(28), below, can beused in PEALD processes.

N Precursors

As discussed above, the second precursor according to the presentdisclosure may comprise a nitrogen precursor. In some embodiments thesecond precursor in a PEALD process may comprise a reactive species.Suitable plasma compositions include nitrogen plasma, radicals ofnitrogen, or atomic nitrogen in one form or another. In someembodiments, the reactive species may comprise N-containing plasma or aplasma comprising N. In some embodiments, the reactive species maycomprise a plasma comprising N-containing species. In some embodimentsthe reactive species may comprise nitrogen atoms and/or N* radicals. Insome embodiments, hydrogen plasma, radicals of hydrogen, or atomichydrogen in one form or another are also provided. And in someembodiments, a plasma may also contain noble gases, such as He, Ne, Ar,Kr and Xe, preferably Ar or He, in plasma form, as radicals, or inatomic form. In some embodiments, the second precursor does not compriseany species from a noble gas, such as Ar. Thus, in some embodimentsplasma is not generated in a gas comprising a noble gas.

Thus, in some embodiments the second precursor may comprise plasmaformed from compounds having both N and H, such as NH3 and N2H4, amixture of N2/H2 or other precursors having an N—H bond. In someembodiments the second precursor may be formed, at least in part, fromN2. In some embodiments the second precursor may be formed, at least inpart, from N2 and H2, where the N2 and H2 are provided at a flow ratio(N2/H2) from about 20:1 to about 1:20, preferably from about 10:1 toabout 1:10, more preferably from about 5:1 to about 1:5 and mostpreferably from about 1:2 to about 4:1, and in some cases 1:1.

The second precursor may be formed in some embodiments remotely viaplasma discharge (“remote plasma”) away from the substrate or reactionspace. In some embodiments, the second precursor may be formed in thevicinity of the substrate or directly above substrate (“direct plasma).

FIG. 1 is a flow chart generally illustrating a depositing a layer on asubstrate in a reactor in accordance with some embodiments. According tocertain embodiment, the process may comprise the following:

(1) a substrate comprising a three-dimensional structure is provided ina reaction space;

(2) a silicon halide precursor, such as SiI2H2, is introduced into thereaction space so that silicon-containing species are adsorbed to asurface of the substrate;

(3) excess silicon halide precursor and reaction byproducts aresubstantially removed from the reaction space;

(4) a nitrogen-containing precursor, such as N2, NH3, N2H4, or N2 andH2, is introduced into the reaction, and reactive species from thenitrogen precursor are created and the reactive species are contactedwith the substrate; and

(5) removing excess nitrogen atoms, plasma, or radicals and reactionbyproducts;

Steps (2) through (5) of the silicon nitride deposition cycle (7) may berepeated (6) until a silicon nitride film of a desired thickness isformed for the primary layer. The temperature of the substrate may bebetween 25 to 700° C. preferably from about 50° C. to about 600° C.,more preferably from about 100° C. to about 550° C., and most preferablyfrom about 200° C. to about 400° C. during providing a plasma gas andproviding an energy source to create the plasma.

Nitrogen may flow continuously throughout the silicon nitride depositioncycle, with nitrogen plasma formed at the appropriate times to convertadsorbed silicon compound into silicon nitride.

As mentioned above, in some embodiments the substrate may be contactedsimultaneously with the silicon compound and the reactive species toform the primary layer in a plasma enhanced chemical vapor deposition(PECVD) process.

The process may further comprise:

(8) stopping the introduction of the second precursor if the primarylayer has reached a required thickness. The required thickness may bepreset to a value of about 1 nm to about 50 nm, preferably from about 3nm to about 30 nm, and more preferably from about 4 nm to about 15 nm.Subsequently, the silicon halide precursor may be introduced in thereactor at a temperature causing decomposition of the silicon halideprecursor to provide a substantially pure amorphous silicon layer on topof the primary layer.

The substrate may be heated to a temperature between 400 to 900° C.,preferably between 450 and 700° C., more preferably between 500 and 600°C., and even more preferable around 550° C. to decompose the siliconhalide precursor in the reactor. The substantially pure amorphoussilicon layer may be deposed at an increasing pressure when it is donewithout a plasma. The primary layer comprising silicon and the secondprecursor and the substantially pure amorphous silicon layer may have animproved etch rate when combined.

After stopping the introduction of the second precursor if the primarylayer has reached a required thickness in (8) the silicon halideprecursor may be introduced in the reactor at a temperature causingdecomposition of the silicon halide precursor to provide a substantiallypure amorphous silicon layer on top of the primary layer. Duringdepositing the substantially pure amorphous silicon layer a nitrogen andoxygen poor plasma gas comprising helium, hydrogen and/or argon may beprovided. An energy source may create a plasma from the plasma gas so toactivate the silicon precursor. If a plasma is used the temperature maybe lowered to between 20 to 400° C. preferably 100 to 300° C. duringdepositing the substantially pure silicon layer. The primary andsubstantially pure amorphous silicon layer may advantageously beprovided in the same reactor chamber.

The layer comprising the primary layer comprising silicon and secondprecursor, and the substantially pure amorphous silicon layer on top mayhave an improved etch rate. The amorphous silicon may function as a skinor armor layer on top of the SiN layer for example to protect against anhydrogen fluoride (HF) etch.

The layer may be easily deposited because no different first precursoris required for the primary and substantially pure amorphous siliconlayer. Further no different tool nor any transfer to a differentreaction chamber may be necessary. The pure amorphous silicon layer maybe selective to the primary layer such that it is only deposited on topof this layer. We can use the process to make Si rich SiN which willhave high RI value and low WER. We can use it in combination with thetemporal selectivity property of the silicon precursor because amorphoussilicon may have a preferential growth on SiN.

According to some embodiments, a silicon nitride layer and an amorphoussilicon layer on top is deposited using a plasma enhanced chemical vapordeposition PEALD process on a substrate having three-dimensionalfeatures, such as in a FinFET application. The features may have anaspect ratios of more than 2, preferably an aspect ratios of more than3, more preferably an aspect ratios of more than 6 and most preferablyan aspect ratios of more than 11. The process may comprise the steps asdescribed above in conjunction with FIG. 1.

As described above the method may comprise depositing a pure amorphoussilicon layer on top of a silicon nitride layer. The method may also bethe other way around and comprising depositing a silicon nitride layeron top of a pure amorphous silicon layer creating a silicon layer with asilicon nitride crust resulting in a very high wet etch rate intetramethylammonium hydroxide (TMAH).

The method may comprise depositing a silicon nitride layer on top of anamorphous layer on top of an silicon nitride layer on top of anamorphous layer in any ratio to create a multilayered cover. Themultilayered cover allows to tune the stress, RI, etch properties of anSixNy layer system.

Thermal ALD Processes

The methods presented herein also allow deposition of silicon nitridefilms on substrate surfaces by thermal ALD processes. Geometricallychallenging applications, such as 3-dimensional structures, are alsopossible with these thermal processes. According to some embodiments,thermal atomic layer deposition (ALD) type processes are used to formsilicon nitride films on substrates such as integrated circuitworkpieces.

A substrate or workpiece is placed in a reaction chamber and subjectedto alternately repeated, self-limiting surface reactions. Preferably,for forming silicon nitride films each thermal ALD cycle comprises atleast two distinct phases. The provision and removal of a precursor fromthe reaction space may be considered a phase. In a first phase, a firstprecursor comprising silicon is provided and forms no more than aboutone monolayer on the substrate surface. This precursor is also referredto herein as “the silicon precursor” or “silicon reactant” and may be,for example, a silicon halide such as H₂SiI₂. In a second phase, asecond precursor comprising a nitrogen-containing compound is providedand reacts with the adsorbed silicon precursor to form SiN. This secondprecursor may also be referred to as a “nitrogen precursor” or “nitrogenreactant.” The second precursor may comprise NH₃ or another suitablenitrogen-containing compound. Additional phases may be added and phasesmay be removed as desired to adjust the composition of the final film.

One or more of the precursors may be provided with the aid of a carriergas, such as Ar or He. In some embodiments the silicon precursor and thenitrogen precursor are provided with the aid of a carrier gas.

In some embodiments, two of the phases may overlap, or be combined. Forexample, the silicon precursor and the nitrogen precursor may beprovided simultaneously in pulses that partially or completely overlap.In addition, although referred to as the first and second phases, andthe first and second precursors, the order of the phases and the orderof provision of precursors may be varied, and an ALD cycle may beginwith any one of the phases or any of the precursors. That is, unlessspecified otherwise, the precursors can be provided in any order and theprocess may begin with any of the precursors.

As discussed in more detail below, in some embodiments for depositing asilicon nitride film, one or more deposition cycles typically beginswith provision of the silicon precursor followed by the nitrogenprecursor. In some embodiments, one or more deposition cycles beginswith provision of the nitrogen precursor followed by the siliconprecursor.

Again, one or more of the precursors may be provided with the aid of acarrier gas, such as Ar or He. In some embodiments the nitrogenprecursor is provided with the aid of a carrier gas. In someembodiments, although referred to as a first phase and a second phaseand a first and second precursor, the order of the phases and thus theorder of provision of the precursors may be varied, and an ALD cycle maybegin with any one of the phases.

In some embodiments the substrate on which deposition is desired, suchas a semiconductor workpiece, is loaded into a reactor. The reactor maybe part of a cluster tool in which a variety of different processes inthe formation of an integrated circuit are carried out. In someembodiments a flow-type reactor is utilized. In some embodiments ashower head type of reactor is utilized. In some embodiments a spacedivided reactor is utilized. In some embodiments a high-volumemanufacturing-capable single wafer ALD reactor is used. In otherembodiments a batch reactor comprising multiple substrates is used. Forembodiments in which batch ALD reactors are used, the number ofsubstrates is preferably in the range of 10 to 200, more preferably inthe range of 50 to 150, and most preferably in the range of 100 to 130.

Exemplary single wafer reactors, designed specifically to enhance ALDprocesses, are commercially available from ASM America, Inc. (Phoenix,Ariz.) under the tradenames Pulsar® 2000 and Pulsar® 3000 and ASM JapanK.K (Tokyo, Japan) under the tradename Eagle® XP, XP8 and Dragon®.Exemplary batch ALD reactors, designed specifically to enhance ALDprocesses, are commercially available from and ASM Europe B.V (Almere,Netherlands) under the tradenames A400™ and A412™.

In some embodiments, if necessary, the exposed surfaces of the workpiececan be pretreated to provide reactive sites to react with the firstphase of the ALD process. In some embodiments a separate pretreatmentstep is not required. In some embodiments the substrate is pretreated toprovide a desired surface termination.

In some embodiments, excess precursor and reaction byproducts, if any,are removed from the vicinity of the precursor, such as from thesubstrate surface, between precursor pulses. In some embodiments excessprecursor and reaction byproducts are removed from the reaction chamberby purging between precursor pulses, for example with an inert gas. Theflow rate and time of each precursor, is tunable, as is the purge step,allowing for control of the quality and properties of the films. In someembodiments removing excess precursor and/or reaction byproductscomprises moving the substrate.

As mentioned above, in some embodiments, a gas is provided to thereaction chamber continuously during each deposition cycle, or duringthe entire ALD process. In other embodiments the gas may be nitrogen,helium or argon.

The ALD cycle is repeated until a primary layer of the desired thicknessand composition is obtained. In some embodiments the depositionparameters, such as the flow rate, flow time, purge time, and/orprecursors themselves, may be varied in one or more deposition cyclesduring the ALD process in order to obtain a film with the desiredcharacteristics.

The term “pulse” may be understood to comprise feeding precursor intothe reaction chamber for a predetermined amount of time. The term“pulse” does not restrict the length or duration of the pulse and apulse can be any length of time.

In some embodiments, the silicon precursor is provided first. After aninitial surface termination, if necessary or desired, a first siliconprecursor pulse is supplied to the workpiece. In accordance with someembodiments, the first precursor pulse comprises a carrier gas flow anda volatile silicon species, such as H₂SiI₂, that is reactive with theworkpiece surfaces of interest. Accordingly, the silicon precursoradsorbs upon the workpiece surfaces. The first precursor pulseself-saturates the workpiece surfaces such that any excess constituentsof the first precursor pulse do not substantially react further with themolecular layer formed by this process.

The first silicon precursor pulse is preferably supplied in gaseousform. The silicon precursor gas is considered “volatile” for purposes ofthe present description if the species exhibits sufficient vaporpressure under the process conditions to transport the species to theworkpiece in sufficient concentration to saturate exposed surfaces.

In some embodiments the silicon precursor pulse is from about 0.05seconds to about 5.0 seconds, about 0.1 seconds to about 3 seconds orabout 0.2 seconds to about 1.0 second. In batch process the siliconprecursor pulses can be substantially longer as can be determined by theskilled artisan given the particular circumstances.

After sufficient time for a molecular layer to adsorb on the substratesurface, excess first precursor is then removed from the reaction space.In some embodiments the excess first precursor is purged by stopping theflow of the first precursor while continuing to flow a carrier gas orpurge gas for a sufficient time to diffuse or purge excess precursorsand reaction by-products, if any, from the reaction space.

In some embodiments, the first precursor is purged for about 0.1 secondsto about 10 seconds, about 0.3 seconds to about 5 seconds or about 0.3seconds to about 1 seconds. Provision and removal of the siliconprecursor can be considered the first or silicon phase of the ALD cycle.In batch process the first precursor purge can be substantially longeras can be determined by the skilled artisan given the specificcircumstances.

A second, nitrogen precursor is pulsed into the reaction space tocontact the substrate surface. The nitrogen precursor may be providedwith the aid of a carrier gas. The nitrogen precursor may be, forexample, NH₃ or N₂H₄. The nitrogen precursor pulse is also preferablysupplied in gaseous form. The nitrogen precursor is considered“volatile” for purposes of the present description if the speciesexhibits sufficient vapor pressure under the process conditions totransport the species to the workpiece in sufficient concentration tosaturate exposed surfaces.

In some embodiments, the nitrogen precursor pulse is about 0.05 secondsto about 5.0 seconds, 0.1 seconds to about 3.0 seconds or about 0.2seconds to about 1.0 second. In batch process the nitrogen precursorpulses can be substantially longer as can be determined by the skilledartisan given the specific circumstances.

After sufficient time for a molecular layer to adsorb on the substratesurface at the available binding sites, the second, nitrogen precursoris then removed from the reaction space. In some embodiments the flow ofthe second nitrogen precursor is stopped while continuing to flow acarrier gas for a sufficient time to diffuse or purge excess precursorsand reaction by-products, if any, from the reaction space, preferablywith greater than about two reaction chamber volumes of the purge gas,more preferably with greater than about three chamber volumes. Provisionand removal of the nitrogen precursor can be considered the second ornitrogen phase of the ALD cycle.

In some embodiments, the nitrogen precursor is purged for about 0.1seconds to about 10.0 seconds, about 0.3 seconds to about 5.0 seconds orabout 0.3 seconds to about 1.0 second. In batch process the firstprecursor purge can be substantially longer as can be determined by theskilled artisan given the specific circumstances.

The flow rate and time of the nitrogen precursor pulse, as well as theremoval or purge step of the nitrogen phase, are tunable to achieve adesired composition in the silicon nitride film. Although the adsorptionof the nitrogen precursor on the substrate surface is typicallyself-limiting, due to the limited number of binding sites, pulsingparameters can be adjusted such that less than a monolayer of nitrogenis adsorbed in one or more cycles.

The two phases together represent one ALD cycle, which is repeated toform silicon nitrogen thin films of the desired thickness. While the ALDcycle is generally referred to herein as beginning with the siliconphase, it is contemplated that in other embodiments the cycle may beginwith the nitrogen phase. One of skill in the art will recognize that thefirst precursor phase generally reacts with the termination left by thelast phase in the previous cycle. In some embodiments one or moredifferent ALD cycles are provided in the deposition process.

According to some embodiments of the present disclosure, ALD reactionsmay be performed at temperatures ranging from about 25° C. to about1000° C., preferably from about 100° C. to about 800° C., morepreferably from about 200° C. to about 650° C., and most preferably fromabout 300° C. to about 500° C. In some embodiments, the optimum reactortemperature may be limited by the maximum allowed thermal budget.Therefore, the reaction temperature can be from about 300° C. to about400° C. In some applications, the maximum temperature is around about400° C., and, therefore, the process is run at that reactiontemperature.

Si Precursors

A number of suitable silicon precursors may be used in the presentlydisclosed processes. These silicon precursors may be used in thermal ALDprocesses. In some embodiments these precursors may also be used inplasma ALD or plasma CVD processes. In some embodiments these precursorsmay be introduced in the reactor at a temperature causing decompositionof the silicon halide precursor to provide a second substantially pureamorphous silicon layer on top of the primary layer thereby a layer witha desired quality (at least one of the desired WER, WERR, patternloading effect or/and step coverage features described below) isdeposited.

According to some embodiments, some silicon precursors comprise iodineand the film deposited by using that precursor has at least one desiredproperty, for example at least one of the desired WER, WERR, patternloading effect or/and step coverage features described below.

According to some embodiments, some silicon precursors comprise bromineand the film deposited by using that precursor have at least one desiredproperty, for example at least one of the desired WER, WERR, patternloading effect or/and step coverage features described below.

At least some of the suitable precursors may have the following generalformula:H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)R_(w)  (9)wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R is an organic ligand and can be independentlyselected from the group consisting of alkoxides, alkylsilyls, alkyl,substituted alkyl, alkylamines and unsaturated hydrocarbon; preferablyn=1-5 and more preferably n=1-3 and most preferably 1-2. Preferably R isa C₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more cyclic compounds. Such precursors may have the followinggeneral formula:H_(2n+2−y−z−w)Si_(n)I_(y)A_(z)R_(w)  (10)wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), X is I or Br, A is a halogenother than X, R is an organic ligand and can be independently selectedfrom the group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=3-6.Preferably R is a C1-C3 alkyl ligand, such as methyl, ethyl, n-propyl orisopropyl.

According to some embodiments, some silicon halide precursors compriseone or more iodosilanes. Such precursors may have the following generalformula:H_(2n−y−z−w)Si_(n)I_(y)A_(z)R_(w)  (11)wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), A is a halogen otherthan I, R is an organic ligand and can be independently selected fromthe group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=1-5 andmore preferably n=1-3 and most preferably 1-2. Preferably R is a C1-C3alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more cyclic iodosilanes. Such precursors may have the followinggeneral formula:H_(2n+2−y−z−w)Si_(n)I_(y)A_(z)R_(w)  (12)wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), A is a halogen other than I, Ris an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon; preferably n=3-6. Preferably Ris a C1-C3 alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon halide precursors compriseone or more bromosilanes. Such precursors may have the following generalformula:H_(2n+2−y−z−w)Si_(n)Br_(y)A_(z)R_(w)  (13)wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), A is a halogen otherthan Br, R is an organic ligand and can be independently selected fromthe group consisting of alkoxides, alkylsilyls, alkyl, substitutedalkyl, alkylamines and unsaturated hydrocarbon; preferably n=1-5 andmore preferably n=1-3 and most preferably 1-2. Preferably R is a C1-C3alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon precursors comprise one ormore cyclic bromosilanes. Such precursors may have the following generalformula:H_(2n−y−z−w)Si_(n)Br_(y)A_(z)R_(w)  (14)wherein, n=3-10, y=1 or more (and up to 2n−z−w), z=0 or more (and up to2n−y−w), w=0 or more (and up to 2n−y−z), A is a halogen other than Br, Ris an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon; preferably n=3-6. Preferably Ris a C1-C3 alkyl ligand such as methyl, ethyl, n-propyl or isopropyl.

According to some embodiments, some silicon precursors comprise one ormore iodosilanes or bromosilanes in which the iodine or bromine is notbonded to the silicon in the compound. Accordingly some suitablecompounds may have iodine/bromine substituted alkyl groups. Suchprecursors may have the following general formula:H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)R^(II) _(w)  (15)wherein, n=1-10, y=0 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R^(II) is an organic ligand containing I or Br andcan be independently selected from the group consisting of I or Brsubstituted alkoxides, alkylsilyls, alkyls, alkylamines and unsaturatedhydrocarbons; preferably n=1-5 and more preferably n=1-3 and mostpreferably 1-2. Preferably R^(II) is an iodine substituted C₁-C₃ alkylligand.

According to some embodiments, some silicon precursors comprise one ormore cyclic iodosilanes or bromosilanes. Accordingly some suitablecyclic compounds may have iodine/bromine substituted alkyl groups. Suchprecursors may have the following general formula:H_(2n−y−z−w)Si_(n)X_(y)A_(z)R^(II) _(w)  (16)wherein, n=3-10, y=0 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R^(II) is an organic ligand containing I or Br andcan be independently selected from the group consisting of I or Brsubstituted alkoxides, alkylsilyls, alkyls, alkylamines and unsaturatedhydrocarbons; preferably n=3-6. Preferably R is an iodine substitutedC₁-C₃ alkyl ligand.

According to some embodiments, some suitable silicon precursors may haveat least one of the following general formulas:H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)(NR₁R₂)_(w)  (17)wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, N is nitrogen and R1 and R2 can be independentlyselected from the group consisting of hydrogen, alkyl, substitutedalkyl, silyl, alkylsilyl and unsaturated hydrocarbon; preferably n=1-5and more preferably n=1-3 and most preferably 1-2. Preferably R₁ and R₂are hydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂)_(w) ligands can beindependently selected from each other.(H_(3−y−z−w)X_(y)A_(z)(NR₁R₂)_(w)Si)₃—N  (18)wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=1 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, N is nitrogen and R₁ and R₂ can be independently selected from thegroup consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon. Preferably R₁ and R₂ arehydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂), ligands can be independentlyselected from each other. Each of the threeH_(3−y−z−w)X_(y)A_(z)(NR₁R₂)_(w) Si ligands can be independentlyselected from each other.

In some embodiments, some suitable precursors may have at least one ofthe following more specific formulas:H_(2n+2−y−w)Si_(n)I_(y)(NR₁R₂)_(w)  (19)wherein, n=1-10, y=1 or more (and up to 2n+2−w), w=1 or more (and up to2n+2−y), N is nitrogen, and R₁ and R₂ can be independently selected fromthe group consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon; preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2. Preferably R₁ and R₂ arehydrogen or C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl and n-butyl. More preferably R₁and R₂ are hydrogen or C₁-C₃ alkyl groups, such as methyl, ethyl,n-propyl or isopropyl. Each of the (NR₁R₂)_(w) ligands can beindependently selected from each other.(H_(3−y−w)I_(y)(NR₁R₂)_(w)Si)₃—N  (20)wherein, y=1 or more (and up to 3−w), w=1 or more (and up to 3−y), N isnitrogen and R₁ and R₂ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon. Preferably R₁ and R₂ are hydrogen or C₁-C₄alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl and n-butyl. More preferably R₁ and R₂ are hydrogenor C₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl or isopropyl.Each of the three H_(3−y−w)I_(y)(NR₁R₂)_(w)Si ligands can beindependently selected from each other.

According to some embodiments, some suitable silicon precursors may haveat least one of the following general formulas:H_(2n+2−y−z−w)Si_(n)X_(y)A_(z)(NR₁R₂)_(w)  (21)wherein, n=1-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=1 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, N is nitrogen, R₁ can be independently selectedfrom the group consisting of hydrogen, alkyl, substituted alkyl, silyl,alkylsilyl, and unsaturated hydrocarbon, and R₂ can be independentlyselected from the group consisting of alkyl, substituted alkyl, silyl,alkylsilyl and unsaturated hydrocarbon; preferably n=1-5 and morepreferably n=1-3 and most preferably 1-2. Preferably R₁ is hydrogen orC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₁ is hydrogen orC₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl, or isopropyl.Preferably R₂ is C₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl,isopropyl, t-butyl, isobutyl, sec-butyl, and n-butyl. More preferably R₂is C₁-C₃ alkyl groups, such as methyl, ethyl, n-propyl, or isopropyl.Each of the (NR₁R₂)_(w) ligands can be independently selected from eachother.(H_(3−y−z−w)X_(y)A_(z)(NR₁R₂)_(w)Si)₃—N  (22)wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=1 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, N is nitrogen, R₁ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon, and R₂ can be independently selected from thegroup consisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂)_(w) ligands can be independently selected from each other.

In some embodiments, some suitable precursors may have at least one ofthe following more specific formulas:H_(2n+2−y−w)Si_(n)I_(y)(NR₁R₂)_(w)  (23)

wherein, n=1-10, y=1 or more (and up to 2n+2−w), w=1 or more (and up to2n+2−y), N is nitrogen, R₁ can be independently selected from the groupconsisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon, and R₂ can be independently selected from thegroup consisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂)_(w) ligands can be independently selected from each other.(H_(3−y−w)I_(y)(NR₁R₂)_(w)Si)₃—N  (24)wherein, y=1 or more (and up to 3−w), w=1 or more (and up to 3−y), N isnitrogen, R₁ can be independently selected from the group consisting ofhydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturatedhydrocarbon, and R₂ can be independently selected from the groupconsisting of alkyl, substituted alkyl, silyl, alkylsilyl, andunsaturated hydrocarbon; preferably n=1-5 and more preferably n=1-3 andmost preferably 1-2. Preferably R₁ is hydrogen or C₁-C₄ alkyl groups,such as methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl,sec-butyl, and n-butyl. More preferably R₁ is hydrogen or C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Preferably R₂ isC₁-C₄ alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, t-butyl,isobutyl, sec-butyl, and n-butyl. More preferably R₂ is C₁-C₃ alkylgroups, such as methyl, ethyl, n-propyl, or isopropyl. Each of the(NR₁R₂)_(w) ligands can be independently selected from each other.

According to some embodiments of a thermal ALD process, suitable siliconhalide precursors can include at least compounds having any one of thegeneral formulas (9) through (24). In general formulas (9) through (18)as well as in general formulas (21) and (22), halides/halogens caninclude F, Cl, Br and I.

In some embodiments, a silicon precursor comprises one or more of thefollowing: SiI₄, HSiI₃, H₂SiI₂, H₃SiI, Si₂I₆, HSi₂I₅, H₂Si₂I₄, H₃Si₂I₃,H₄Si₂I₂, H₅Si₂I, Si₃I₈, HSi₂I₅, H₂Si₂I₄, H₃Si₂I₃, H₄Si₂I₂, H₅Si₂I,MeSiI₃, Me₂SiI₂, Me₃SiI, MeSi₂I₅, Me₂Si₂I₄, Me₃Si₂I₃, Me₄Si₂I₂, Me₅Si₂I,HMeSiI₂, HMe₂SiI, HMeSi₂I₄, HMe₂Si₂I₃, HMe₃Si₂I₂, HMe₄Si₂I, H₂MeSiI,H₂MeSi₂I₃, H₂Me₂Si₂I₂, H₂Me₃Si₂I, H₃MeSi₂I₂, H₃Me₂Si₂I, H₄MeSi₂I,EtSiI₃, Et₂SiI₂, Et₃SiI, EtSi₂I₅, Et₂Si₂I₄, Et₃Si₂I₃, Et₄Si₂I₂, Et₅Si₂I,HEtSiI₂, HEt₂SiI HEtSi₂I₄, HEt₂Si₂I₃, HEt₃Si₂I₂, H₂EtSiI, H₂EtSi₂I₃,H₂Et₂Si₂I₂, H₂Et₃Si₂I, H₃EtSi₂I₂, H₃Et₂Si₂I, and H₄EtSi₂I.

In some embodiments, a silicon halide precursor comprises one or more ofthe following: EtMeSiI₂, Et₂MeSiI, EtMe₂SiI, EtMeSi₂I₄, Et₂MeSi₂I₃,EtMe₂Si₂I₃, Et₃MeSi₂I₂, Et₂Me₂Si₂I₂, EtMe₃Si₂I₂, Et₄MeSi₂I, Et₃Me₂Si₂I,Et₂Me₃Si₂I, EtMe₄Si₂I, HEtMeSiI, HetMeSi₂I₃, HEt₂MeSi₂I₂, HEtMe₂Si₂I₂,HEt₃MeSi₂I, HEt₂Me₂Si₂I, HEtMe₃Si₂I, H₂EtMeSi₂I₂, H₂Et₂MeSi₂I,H₂EtMe₂Si₂I, H₃EtMeSi₂I.

In some embodiments, a silicon halide precursor comprises one or more ofthe following: HSiI₃, H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, H₅Si₂I, MeSiI₃,Me₂SiI₂, Me₃SiI, Me₂Si₂I₄, Me₄Si₂I₂, HMeSiI_(z), H₂Me₂Si₂I₂, EtSiI₃,Et₂SiI₂, Et₃SiI, Et₂Si₂I₄, Et₄Si₂I₂, and HEtSiI₂. In some embodiments asilicon precursor comprises two, three, four, five, six, seven, eight,nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen,seventeen, eighteen, nineteen or more compounds selected from HSiI₃,H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, H₅Si₂I, MeSiI₃, Me₂SiI₂, Me₃SiI,Me₂Si₂I₄, Me₄Si₂I₂, HMeSiI_(z), H₂Me₂Si₂I₂, EtSiI₃, Et₂SiI₂, Et₃SiI,Et₂Si₂I₄, Et₄Si₂I₂, and HEtSiI₂, including any combinations thereof. Incertain embodiments, the silicon precursor is H₂SiI₂.

In some embodiments, a silicon halide precursor comprises three iodinesand one amine or alkylamine ligands bonded to silicon. In someembodiments silicon halide precursor comprises one or more of thefollowing: (SiI₃)NH₂, (SiI₃)NHMe, (SiI₃)NHEt, (SiI₃)NH^(i)Pr,(SiI₃)NH^(t)Bu, (SiI₃)NMe₂, (SiI₃)NMeEt, (SiI₃)NMe^(i)Pr,(SiI₃)NMe^(t)Bu, (SiI₃)NEt₂, (SiI₃)NEt^(i)Pr, (SiI₃)NEt^(t)Bu,(SiI₃)N^(i)Pr₂, (SiI₃)N^(i)Pr^(t)Bu, and (SiI₃)N^(t)Bu₂. In someembodiments, a silicon halide precursor comprises two, three, four,five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiI₃)NH₂, (SiI₃)NHMe,(SiI₃)NHEt, (SiI₃)NH^(i)Pr, (SiI₃)NH^(t)Bu, (SiI₃)NMe₂, (SiI₃)NMeEt,(SiI₃)NMe^(i)Pr, (SiI₃)NMe^(t)Bu, (SiI₃)NEt₂, (SiI₃)NEt^(i)Pr,(SiI₃)NEt^(t)Bu, (SiI₃)N^(i)Pr₂, (SiI₃)N^(i)Pr^(t)Bu, (SiI₃)N^(t)Bu₂,and combinations thereof. In some embodiments, a silicon halideprecursor comprises two iodines and two amine or alkylamine ligandsbonded to silicon. In some embodiments, silicon halide precursorcomprises one or more of the following: (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂,(SiI₂)(NHEt)₂, (SiI₂)(NH^(i)Pr)₂, (SiI₂)(NH^(t)Bu)₂, (SiI₂)(NMe₂)₂,(SiI₂)(NMeEt)₂, (SiI₂)(NMe^(i)Pr)₂, (SiI₂)(NMe^(t)Bu)₂, (SiI₂)(NEt₂)₂,(SiI₂)(NEt^(i)Pr)₂, (SiI₂)(NEt^(t)Bu)₂, (SiI₂)(N^(i)Pr₂)₂,(SiI₂)(N^(i)Pr^(t)Bu)₂, and (SiI₂)(N^(t)Bu)₂. In some embodiments, asilicon halide precursor comprises two, three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen or morecompounds selected from (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂,(SiI₂)(NH^(i)Pr)₂, (SiI₂)(NH^(t)Bu)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂,(SiI₂)(NMe^(i)Pr)₂, (SiI2)(NMe^(t)Bu)₂, (SiI₂)(NEt₂)₂,(SiI₂)(NEt^(i)Pr)₂, (SiI₂)(NEt^(t)Bu)₂, (SiI₂)(N^(i)Pr)₂,(SiI₂)(N^(i)Pr^(t)Bu)₂, (SiI₂)(N^(t)Bu)₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises two iodines,one hydrogen and one amine or alkylamine ligand bonded to silicon. Insome embodiments silicon halide precursor comprises one or more of thefollowing: (SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NH^(i)Pr,(SiI₂H)NH^(t)Bu, (SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NMe^(i)Pr,(SiI₂H)NMe^(t)Bu, (SiI₂H)NEt₂, (SiI₂H)NEt^(i)Pr, (SiI₂H)NEt^(t)Bu,(SiI₂H)N^(i)Pr₂, (SiI₂H)N^(i)P_(r) ^(t)Bu, and (SiI₂H)N^(t)Bu₂. In someembodiments a silicon halide precursor comprises two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen or more compounds selected from (SiI₂H)NH₂, (SiI₂H)NHMe,(SiI₂H)NHEt, (SiI₂H)NH^(i)Pr, (SiI₂H)NH^(t)Bu, (SiI₂H)NMe₂,(SiI₂H)NMeEt, (SiI₂H)NMe^(i)Pr, (SiI₂H)NMe^(t)Bu, (SiI₂H)NEt₂,(SiI₂H)NEt^(i)Pr, (SiI₂H)NEt^(t)Bu, (SiI₂H)N^(i)Pr₂,(SiI₂H)N^(i)Pr^(t)Bu, (SiI₂H)N^(t)Bu₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine,one hydrogen and two amine or alkylamine ligand bonded to silicon. Insome embodiments, silicon halide precursor comprises one or more of thefollowing: (SiIH)(NH₂)₂, (SiIH)(NHMe)₂, (SiIH)(NHEt)₂,(SiIH)(NH^(i)Pr)₂, (SiIH)(NH^(t)Bu)₂, (SiIH)(NMe₂)₂, (SiIH)(NHMe)₂,(SiIH)(NMe^(i)Pr)₂, (SiIH)(NMe^(t)Bu)₂, (SiIH)(NEt₂)₂,(SiIH)(NEt^(i)Pr)₂, (SiIH)(NEt^(t)Bu)₂, (SiIH)(N^(i)Pr₂)₂,(SiIH)(N^(i)Pr^(t)Bu)₂, and (SiIH)(N^(t)Bu)₂. In some embodiments, asilicon halide precursor comprises two, three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen or morecompounds selected from (SiIH)(NH₂)₂, (SiIH)(NHMe)₂, (SiIH)(NHEt)₂,(SiIH)(NH^(i)Pr)₂, (SiIH)(NH^(t)Bu)₂, (SiIH)(NMe₂)₂, (SiIH)(NMeEt)₂,(SiIH)(NMe^(i)Pr)₂, (SiIH)(NMe^(t)Bu)₂, (SiIH)(NEt₂)₂,(SiIH)(NEt^(i)Pr)₂, (SiIH)(NEt^(t)Bu)₂, (SiIH)(N^(i)Pr₂)₂,(SiIH)(N^(i)Pr^(t)Bu)₂, and (SiIH)(N^(t)Bu)₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine,two hydrogens and one amine or alkylamine ligand bonded to silicon. Insome embodiments silicon precursor comprises one or more of thefollowing: (SiIH₂)NH₂, (SiIH₂)NHMe, (SiIH₂)NHEt, (SiIH₂)NH^(i)r,(SiIH₂)NH^(t)Bu, (SiIH₂)NMe₂, (SiIH₂)NMeEt, (SiIH₂)NMe^(i)Pr,(SiIH₂)NMe^(t)Bu, (SiIH₂)NEt₂, (SiIH₂)NEt^(i)Pr, (SiIH₂)NEt^(t)Bu,(SiIH₂)N^(i)Pr₂, (SiIH2)N^(i)Pr^(t)Bu, and (SiIH₂)N^(t)Bu₂. In someembodiments a silicon precursor comprises two, three, four, five, six,seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen ormore compounds selected from (SiIH₂)NH₂, (SiIH₂)NHMe, (SiIH₂)NHEt,(SiIH₂)NH^(i)Pr, (SiIH₂)NH^(t)Bu, (SiIH₂)NMe₂, (SiIH₂)NMeEt,(SiIH₂)NMe^(i)Pr, (SiIH₂)NMe^(t)Bu, (SiIH₂)NEt₂, (SiIH₂)NEt^(i)Pr,(SiIH₂)NEt^(t)Bu, (SiIH₂)N^(i)Pr₂, (SiIH₂)N^(i)Pr^(t)Bu,(SiIH₂)N^(t)Bu₂, and combinations thereof.

In some embodiments, a silicon halide precursor comprises one iodine andthree amine or alkylamine ligands bonded to silicon. In someembodiments, silicon precursor comprises one or more of the following:(SiI)(NH₂)₃, (SiI)(NHMe)₃, (SiI)(NHEt)₃, (SiI)(NH^(i)Pr)₃,(SiI)(NH^(t)Bu)₃, (SiI)(NMe₂)₃, (SiI)(NMeEt)₃, (SiI)(NMe^(i)Pr)₃,(SiI)(NMe^(t)Bu)₃, (SiI)(NEt₂)₃, (SiI)(NEt^(i)Pr)₃, (SiI)(NEt^(t)Bu)₃,(SiI)(N^(i)Pr₂)₃, (SiI)(N^(i)Pr^(t)Bu)₃, and (SiI)(N^(t)Bu)₃. In someembodiments a silicon precursor comprises two, three, four, five, six,seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen ormore compounds selected from (SiI)(NH₂)₃, (SiI)(NHMe)₃, (SiI)(NHEt)³,(SiI)(NH^(i)Pr)₃, (SiI)(NH^(t)Bu)₃, (SiI)(NMe₂)₃, (SiI)(NMeEt)₃,(SiI)(NMe^(i)Pr)₃, (SiI)(NMe^(t)Bu)₃, (SiI)(NEt₂)₃, (SiI)(NEt^(i)Pr)₃,(SiI)(NEt^(t)Bu)₃, (SiI)(N^(i)Pr₂)₃, (SiI)(N^(i)Pr^(t)Bu)₃,(SiI)(N^(t)Bu)₃, and combinations thereof.

In certain embodiments, a silicon halide precursor comprises twoiodines, hydrogen and one amine or alkylamine ligand or two iodines andtwo alkylamine ligands bonded to silicon and wherein amine or alkylamineligands are selected from amine NH₂—, methylamine MeNH—, dimethylamineMe₂N—, ethylmethylamine EtMeN—, ethylamine EtNH—, and diethylamineEt₂N—. In some embodiments silicon halide precursor comprises one ormore of the following: (SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt,(SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NEt₂, (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂,(SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂, and (SiI₂)(NEt₂)₂. In someembodiments a silicon precursor comprises two, three, four, five, six,seven, eight, nine, ten, eleven, twelve or more compounds selected from(SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NMe₂, (SiI₂H)NMeEt,(SiI₂H)NEt₂, (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂,(SiI₂)(NMeEt)₂, (SiI₂)(NEt₂)₂, and combinations thereof.

Other Types of Si-Precursors Containing I or Br

A number of suitable silicon halide precursors containing nitrogen, suchas iodine or bromine substituted silazanes, or sulphur, may be used inthe presently disclosed thermal and plasma ALD processes. In someembodiments silicon precursors containing nitrogen, such as iodine orbromine substituted silazanes, may be used in the presently disclosedthermal and plasma ALD processes in which a film with desired quality isto be deposited, for example at least one of the desired WER, WERR,pattern loading effect or/and step coverage features described below.

At least some of the suitable iodine or bromine substituted siliconhalide precursors may have the following general formula:H_(2n+2−y−z−w)Si_(n)(EH)_(n−1)X_(y)A_(z)R_(w)  (25)wherein, n=2-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, E is N orS, preferably N, A is a halogen other than X, R is an organic ligand andcan be independently selected from the group consisting of alkoxides,alkylsilyls, alkyl, substituted alkyl, alkylamines and unsaturatedhydrocarbon; preferably n=2-5 and more preferably n=2-3 and mostpreferably 1-2. Preferably R is a C₁-C₃ alkyl ligand, such as methyl,ethyl, n-propyl or isopropyl.

At least some of the suitable iodine or bromine substituted silazaneprecursors may have the following general formula:H_(2n+2−y−z−w)Si_(n)(NH)_(n−1)X_(y)A_(z)R_(w)  (26)wherein, n=2-10, y=1 or more (and up to 2n+2−z−w), z=0 or more (and upto 2n+2−y−w), w=0 or more (and up to 2n+2−y−z), X is I or Br, A is ahalogen other than X, R is an organic ligand and can be independentlyselected from the group consisting of alkoxides, alkylsilyls, alkyl,substituted alkyl, alkylamines and unsaturated hydrocarbon; preferablyn=2-5 and more preferably n=2-3 and most preferably 2. Preferably R is aC₁-C₃ alkyl ligand, such as methyl, ethyl, n-propyl or isopropyl.

In some embodiments, the silicon halide precursor comprises Si-compound,such as heterocyclic Si compound, which comprises I or Br. Such cyclicprecursors may comprise the following substructure:—Si-E-Si—  (27)wherein E is N or S, preferably N.

In some embodiments the silicon halide precursor comprises substructureaccording to formula (27) and example of this kind of compounds is forexample, iodine or bromine substituted cyclosilazanes, such iodine orbromine substituted cyclotrisilazane.

In some embodiments, the silicon halide precursor comprises Si-compound,such as silylamine based compound, which comprises I or Br. Suchsilylamine based Si-precursors may have the following general formula:(H_(3−y−z−w)X_(y)A_(z)R_(w)Si)₃—N  (28)wherein, y=1 or more (and up to 3−z−w), z=0 or more (and up to 3−y−w),w=0 or more (and up to 3−y−z), X is I or Br, A is a halogen other thanX, R is an organic ligand and can be independently selected from thegroup consisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines and unsaturated hydrocarbon. Preferably R is a C₁-C₃ alkylligand, such as methyl, ethyl, n-propyl or isopropyl. Each of the threeH_(3−y−z−w)X_(y)A_(z)R_(w)Si ligands can be independently selected fromeach other.N Precursors

A number of suitable second precursors may be used in the presentlydisclosed processes. These second precursors may be used in thermal ALDprocesses. In some embodiments these precursors may also be used inplasma ALD or plasma CVD processes thereby a layer with a desiredquality (at least one of the desired WER, WERR, pattern loading effector/and step coverage features described below) is deposited.

According to some embodiments, the second precursor or nitrogenprecursor in a thermal ALD process may be NH₃, N₂H₄, or any number ofother suitable nitrogen compounds having a N—H bond.

SiN Film Characteristics

The silicon nitride thin films deposited according to some of theembodiments discussed herein (irrespective of whether the siliconprecursor contained bromine or iodine) may achieve impurity levels orconcentrations below about 3%, preferably below about 1%, morepreferably below about 0.5%, and most preferably below about 0.1%. Insome thin films, the total impurity level excluding hydrogen may bebelow about 5%, preferably below about 2%, more preferably below about1%, and most preferably below about 0.2%. And in some thin films,hydrogen levels may be below about 30%, preferably below about 20%, morepreferably below about 15%, and most preferably below about 10%.

In some embodiments, the deposited SiN films do not comprise anappreciable amount of carbon. However, in some embodiments a SiN filmcomprising carbon is deposited. For example, in some embodiments an ALDreaction is carried out using a silicon precursor comprising carbon anda thin silicon nitride film comprising carbon is deposited. In someembodiments a SiN film comprising carbon is deposited using a precursorcomprising an alkyl group or other carbon-containing ligand. In someembodiments a silicon precursor of one of formulas (9)-(28) andcomprising an alkyl group is used in a PEALD or thermal ALD process, asdescribed above, to deposit a SiN film comprising carbon. Differentalkyl groups, such as Me or Et, or other carbon-containing ligands mayproduce different carbon concentrations in the films because ofdifferent reaction mechanisms. Thus, different precursors can beselected to produce different carbon concentration in deposited SiNfilms. In some embodiments the thin SiN film comprising carbon may beused, for example, as a low-k spacer. In some embodiments the thin filmsdo not comprise argon.

According to some embodiments, the silicon nitride thin films mayexhibit step coverage and pattern loading effects of greater than about50%, preferably greater than about 80%, more preferably greater thanabout 90%, and most preferably greater than about 95%. In some casesstep coverage and pattern loading effects can be greater than about 98%and in some case about 100% (within the accuracy of the measurement toolor method). These values can be achieved in aspect ratios of more than2, preferably in aspect ratios more than 3, more preferably in aspectratios more than 6 and most preferably in aspect ratios more than 11.

As used herein, “pattern loading effect” is used in accordance with itsordinary meaning in this field. While pattern loading effects may beseen with respect to impurity content, density, electrical propertiesand etch rate, unless indicated otherwise the term pattern loadingeffect when used herein refers to the variation in film thickness in anarea of the substrate where structures are present. Thus, the patternloading effect can be given as the film thickness in the sidewall orbottom of a feature inside a three-dimensional structure relative to thefilm thickness on the sidewall or bottom of the three-dimensionalstructure/feature facing the open field. As used herein, a 100% patternloading effect (or a ratio of 1) would represent about a completelyuniform film property throughout the substrate regardless of featuresi.e. in other words there is no pattern loading effect (variance in aparticular film property, such as thickness, in features vs. openfield).

In some embodiments, silicon nitride films are deposited to athicknesses of from about 1 nm to about 50 nm, preferably from about 3nm to about 30 nm, more preferably from about 4 nm to about 15 nm. Thesethicknesses can be achieved in feature sizes (width) below about 100 nm,preferably about 50 nm, more preferably below about 30 nm, mostpreferably below about 20 nm, and in some cases below about 15 nm.According to some embodiments, a SiN film is deposited on athree-dimensional structure and the thickness at a sidewall may bearound 10 nm.

It has been found that in using the silicon nitride thin films of thepresent disclosure, thickness differences between top and side may notbe as critical for some applications, due to the improved film qualityand etch characteristics. Nevertheless, in some embodiments, thethickness gradient along the sidewall may be very important tosubsequent applications or processes.

Amorphous Silicon Layer Characteristics

The substantially pure amorphous silicon (A-Si) layer depositedaccording to some of the embodiments discussed herein (irrespective ofwhether the silicon precursor contained bromine or iodine) may achieveimpurity levels or concentrations below about 3%, preferably below about1%, more preferably below about 0.5%, and most preferably below about0.1%. In some thin films, the total impurity level excluding hydrogenmay be below about 5%, preferably below about 2%, more preferably belowabout 1%, and most preferably below about 0.2%. And in some thin films,hydrogen levels may be below about 30%, preferably below about 20%, morepreferably below about 15%, and most preferably below about 10%.

In some embodiments, the deposited A-Si layer do not comprise anappreciable amount of carbon. However, in some embodiments an A-Si layercomprising carbon is deposited. For example, in some embodiments an ALDreaction is carried out using a silicon precursor comprising carbon anda thin A-Si layer comprising carbon is deposited. In some embodiments aA-Si layer comprising carbon is deposited using a precursor comprisingan alkyl group or other carbon-containing ligand. In some embodiments asilicon precursor of one of formulas (9)-(28) and comprising an alkylgroup is used in a PEALD, PECVD or thermal CVD process, as describedabove, to deposit a A-Si film comprising carbon. In some embodiments thethin SiN film comprising carbon may be used, for example, as a low-kspacer.

According to some embodiments, the A-Si films may exhibit step coverageand pattern loading effects of greater than about 50%, preferablygreater than about 80%, more preferably greater than about 90%, and mostpreferably greater than about 95%. In some cases step coverage andpattern loading effects can be greater than about 98% and in some caseabout 100% (within the accuracy of the measurement tool or method).These values can be achieved in aspect ratios of more than 2, preferablyin aspect ratios more than 3, more preferably in aspect ratios more than6 and most preferably in aspect ratios more than 11.

As used herein, “pattern loading effect” is used in accordance with itsordinary meaning in this field. While pattern loading effects may beseen with respect to impurity content, density, electrical propertiesand etch rate, unless indicated otherwise the term pattern loadingeffect when used herein refers to the variation in film thickness in anarea of the substrate where structures are present. Thus, the patternloading effect can be given as the film thickness in the sidewall orbottom of a feature inside a three-dimensional structure relative to thefilm thickness on the sidewall or bottom of the three-dimensionalstructure/feature facing the open field. As used herein, a 100% patternloading effect (or a ratio of 1) would represent about a completelyuniform film property throughout the substrate regardless of featuresi.e. in other words there is no pattern loading effect (variance in aparticular film property, such as thickness, in features vs. openfield).

In some embodiments, amorphous silicon A-Si films are deposited to athicknesses of from about 0.1 nm to about 40 nm, preferably from about 1nm to about 20 nm, more preferably from about 1.5 nm to about 5 nm.These thicknesses can be achieved in feature sizes (width) below about100 nm, preferably about 50 nm, more preferably below about 30 nm, mostpreferably below about 20 nm, and in some cases below about 15 nm.According to some embodiments, a A-Si film is deposited on athree-dimensional structure and the thickness at a sidewall may beslightly even more than 10 nm.

Specific Contexts for Use of SiN/A-Si Films

The methods and materials described herein can provide films withincreased quality and improved etch properties not only for traditionallateral transistor designs, with horizontal source/drain (S/D) and gatesurfaces, but can also provide improved SiN/A-Si films for use onnon-horizontal (e.g., vertical) surfaces, and on complexthree-dimensional (3D) structures. In certain embodiments, SiN/A-Sifilms are deposited by the disclosed methods on a three-dimensionalstructure during integrated circuit fabrication. The three-dimensionaltransistor may include, for example, double-gate field effecttransistors (DG FET), and other types of multiple gate FETs, includingFinFETs. For example, the silicon nitride/amorphous silicon thin filmsof the present disclosure may be useful in nonplanar multiple gatetransistors, such as FinFETs, where it may be desirable to form silicideon vertical walls, in addition to the tops of the gate, source, anddrain regions.

Example 1

A primary 7 nm silicon nitride thin layer was deposited at 550° C.according to the present disclosure by a PEALD process using H2SiI2 asthe first (silicon) precursor and H2+N2 plasma gas as the second(nitrogen) precursor on a first and second bare Si-substrate (wafer)with native oxide. The second substrate additionally received a secondamorphous silicon layer by constantly flowing H2SiI2 at 550° C. for 5minutes.

The thickness of the layers on the substrates were measured with aspectroscopic ellipsometer. The second substrate has a 2 nm thickerlayer (THK). Substrate 1 and 2 were submitted to a 1.5% hydrogenfluorideetch for four minutes. Again the substrates were measured:

TABLE 1 7 nm 2 nm thk NU % 4 min HF thk NU % WER wafer SiN depo a-Sidepo as depo as depo 1.5% dip post etch post etch (nm/min) 1 x 8.5 0.8 x4.2 6.9 1.1 2 x x 10.6 1.2 x 10 3.3 0.2

The second substrate (Wafer 2) shows significantly (±7 times) lower WERRthan wafer 1, wafer 2 also show better uniformity (NU) after etchindicating that the amorphous silicon layer improves the etch resistanceof the layer significantly in table 1. The amorphous silicon layer Silayer may be oxidize or nitrated after etch as desired.

Example 2

FIGS. 2a and 2b show images from layers deposited according to anembodiment on some high aspect ratio structures. FIG. 2a depicts aprimary layer of silicon nitride SiN with a second amorphous siliconlayer A-Si. In between there may be a very thin interfacial layer (INT)of unknown composition. FIG. 2b depicts an identical layer afterhydrogenfluoride HF 1.5% etch for four minutes.

FIG. 2b shows no significant etching indicating that the amorphoussilicon layer improves the etch resistance of the layer significantly.It can be seen that both a-Si and SiN depo are smooth and conformal.

It will be understood by those of skill in the art that numerous andvarious modifications can be made without departing from the spirit ofthe present invention. The described features, structures,characteristics and precursors can be combined in any suitable manner.Therefore, it should be clearly understood that the forms of the presentinvention are illustrative only and are not intended to limit the scopeof the present invention. All modifications and changes are intended tofall within the scope of the invention, as defined by the appendedclaims.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

What is claimed is:
 1. A method of providing a structure by depositing alayer on a substrate in a reactor; the method comprising: introducing afirst precursor comprising a silicon halide in the reactor; introducinga second precursor in the reactor; providing an energy source to createa plasma from the second precursor so that the second precursor reactswith the first precursor until a primary layer comprising silicon andsecond precursor of a desired thickness is formed; subsequentlyintroducing the silicon halide in the reactor at a temperature causingdecomposition of the silicon halide precursor to provide a substantiallypure amorphous silicon layer on top of the primary layer.
 2. The methodaccording to claim 1, wherein the second precursor comprises nitrogenand the primary layer comprises silicon nitride.
 3. The method accordingto claim 1, wherein the second precursor comprises oxygen and theprimary layer comprises silicon dioxide.
 4. The method according toclaim 1, wherein the method comprises bringing the temperature of thesubstrate to between 25 to 700° C. during introducing the secondprecursor and providing an energy source to create a plasma.
 5. Themethod according to claim 1, wherein the method comprises heating thesubstrate to a temperature between 350 to 900° C. to decompose thesilicon halide in the reactor space.
 6. The method according to claim 1,wherein introducing a silicon halide in the reactor comprises adsorbingthe silicon halide to a surface of the substrate.
 7. The methodaccording to claim 6, wherein the deposition method also comprises afterthe plasma is created contacting adsorbed silicon halide with secondprecursor species of the plasma.
 8. The method according to claim 1,wherein the method is a plasma enhanced atomic layer deposition methodand the deposition method comprises removing excess first precursor andreaction byproducts from the reactor space after introducing the firstprecursor; and, after providing an energy source to create a plasma fromthe second precursor.
 9. The method according to claim 1, wherein themethod to form the primary layer is a plasma enhanced atomic layerdeposition method and the deposition method comprises removing excessfirst precursor and reaction byproducts from the reactor space afterintroducing the first precursor; and, after providing an energy sourceto create a plasma from the second precursor.
 10. The method accordingto claim 1, wherein the method to form the primary layer is a plasmaenhanced chemical vapor deposition method.
 11. The method according toclaim 1, wherein the substantially pure amorphous silicon layer isformed at a temperature below the decomposition temperature, using aPECVD deposition method providing an energy source to create a plasmafrom a gas mixture comprising the silicon precursor and substantiallyfree of oxygen and nitrogen until a substantially pure amorphous siliconlayer of a desired thickness is formed.
 12. The method according toclaim 1, wherein the method to form the substantially pure amorphouslayer is a plasma enhanced atomic layer deposition method and thedeposition method comprises removing excess silicon precursor andreaction byproducts from the reactor space after introducing the siliconprecursor; and, after providing an energy source to create a plasma froma gas mixture substantially free of oxygen and nitrogen to form thesubstantially pure amorphous layer.
 13. The method of claim 1, whereinthe layers are deposited on a structure with an aspect ratio of at least1:3.
 14. The method according to claim 13, wherein the structure willform a semiconductor logic or memory device, preferably a FinFET. 15.The method according to claim 1, wherein the silicon halide precursorcomprises a halogen selected from the group comprising fluorine,chlorine, iodine and bromine.
 16. The method according to claim 1,wherein introducing a vapor-phase silicon precursor in the reactor spaceis accomplished using a carrier gas.
 17. The method according to claim16, wherein the carrier gas comprises a nitrogen carrier gas with a flowof 0.5 to 8 slm.
 18. The method according to claim 16, wherein thecarrier gas comprises an argon carrier gas with a flow of 0.5 to 8 slue.19. The method according to claim 1, wherein the pressure in the reactoris between 0.01 torr to 50 torr.
 20. The method according to claim 1,wherein the plasma is created with an energy source having a powerbetween 50 and 1500 Watt.
 21. The method according to claim 1, whereinthe second precursor is introduced with a carrier gas comprising argon,helium or hydrogen with a flow of 1 to 10 slm.
 22. The method accordingto claim 11, wherein the gas mixture used for the plasma comprisesargon, helium or hydrogen introduced with a flow of 1 to 10 slm.
 23. Themethod according to claim 1 wherein the substantially pure amorphoussilicon layer on top of the primary layer changes the etch properties ofthe primary layer to the etch properties of the substantially pureamorphous silicon layer.
 24. The method according to claim 1, whereinthe substantially pure amorphous silicon layer is less than 10 nm thick.25. The method according to claim 1, wherein the primary andsubstantially pure amorphous silicon layer are provided in the samereactor chamber.
 26. The method according to claim 1, wherein depositingthe substantially pure amorphous silicon layer comprises increasing thepressure and/or temperature.
 27. The method according to claim 1,wherein a nanolaminate of silicon/silicon dioxide/silicon nitride isformed in any ratio or order until the nanolaminate layer reaches thedesired thickness.
 28. The method according to claim 27 wherein theproperties (WER, DER, stress, RI) have been tuned by adjusting the ratioand order of the silicon/silicon dioxide/silicon nitride nanolaminatelayer.